1. Center for Electronic Materials; Post-Silicon Semiconductor Institute; Korea Institute of Science and Technology (KIST); Seoul 02792 Republic of Korea
2. Division of Nano & Information Technology, KIST School; Korea University of Science and Technology (KUST); Seoul 02792 Republic of Korea
3. Department of Electronic Engineering; Inha University; Incheon 22201 Republic of Korea
4. Department of Physics; Kunsan National University; Gunsan 54150 Republic of Korea
5. Department of Nano Applied Engineering; Kangwon National University; Chuncheon 24341 Republic of Korea
6. Department of Energy Science; Sungkyunkwan University; Suwon 16419 Republic of Korea
7. Center of Opto-Electronic Materials and Devices; Post-Silicon Semiconductor Institute; Korea Institute of Science and Technology (KIST); Seoul 02792 Republic of Korea